This project is designed to determine the role of mycoplasmas in both animal and human disease and to elucidate the mechanisms of pathogenesis of mycoplasmal diseases with particular emphasis on experimental arthritis. The role of cell-mediated immune responses in the inflammatory process will be defined as will the various interactions of mycoplasmas with normal lymphocyte populations. A new model of mycoplasma-induced rabbit synovitis will be studied in depth. BIBLIOGRAPHIC REFERENCES: Cole, B.C., L. Golightly-Rowland and J.R. Ward, 1976. Arthritis of mice induced by Mycoplasma arthritidis: humoral antibody and lymphocyte of CBA mice. Ann. Rheum. Dis. 35:14-22. Cole, B.C., J.C. Overall, Jr., P.S. Lombardi and L.A. Glasgow, 1976. Induction of interferon in ovine and human lymphocyte cultures by mycoplasmas. Infect. Immun. 14:88-94.